YouTube has come to define the era of online video, so let's take a look at its most popular videos of all time. Our latest update has Justin Bieber still at number 1 with Baby, which was the first video to earn a half a billion views! Currently, Bieber and Eminem between them make almost half of the top 10. Also of note is a music video by Jennifer Lopez called On The Floor ft. Pitbull, which has risen to number 2 with 500 million views in less than a year.

We first did this list in August 2007, at which point Evolution of Dance by comedian Judson Laipply was number 1 with nearly 56 million views (it's now outside the top 10). The next update was September 2008, when Avril Lavigne's Girlfriend pop music video was number 1 with 103 million views. In January 2010, Charlie bit my finger - again ! was number 1, with 148 million views. By the beginning of January 2011, Justin Bieber was at number 1 with over 400 million views for Baby.

Here is the top 10, as of May 2012: